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On average, an asteroid with a diameter of 500 meters can be expected to impact Earth about every 130,000 years or so.[10]

A 2010 dynamical study by Andrea Milani and collaborators had located a series of eight potential Earth impacts between 2169 and 2199. The cumulative probability of impact is dependent on physical properties of the object that were poorly known at the time, but was not found to exceed 0.07% for all eight encounters.[11] The authors recognized that an accurate assessment of 101955 Bennu's probability of Earth impact would require a detailed shape model of 101955 Bennu and additional observations (either from the ground or from spacecraft visiting the object) to determine the magnitude of the Yarkovsky acceleration.

After the publication of the shape model and astrometry based on radar observations obtained in 1999, 2005, and 2011,[3] it was possible to estimate the Yarkovsky acceleration and to revise the impact assessment. The current (as of 2014) best estimate of the impact probability is a cumulative probability of 0.037% in the interval 2175 to 2196.[12] This corresponds to a score on the Palermo scale of −1.70.

Separately, 101955 Bennu has been considered many times as the target of spacecraft missions, including OSIRIS-REx, due to the low Δv[13] required to reach it from Earth orbit. NASA announced on May 25, 2011, that OSIRIS-REx had been selected as part of NASA's New Frontiers Program.[7] The spacecraft is scheduled to launch in 2016, reach 101955 Bennu in 2019 and return samples to Earth in 2023.[7]

People can have their names inscribed on a microchip in the OSIRIS-REx spacecraft.[14]

Bennu was named by Michael Puzio, a third-grader from North Carolina, one of more than eight thousand students from dozens of countries around the world who entered a "Name That Asteroid!" contest run by the University of Arizona, The Planetary Society, and the LINEAR Project, according to The Planetary Report, June 2013. Its name refers to the Egyptian mythological bird Bennu, which Puzio thought the spacecraft, OSIRIS-REx, including its TAGSAM arm, resembled.[15]